Pneumatic safety edge for power operated door



N. K. MILLER 3,303,303 PNEUMATIC SAFETY EDGE FOR POWER OPERATED DOOR Feb. 7, 1967 Filed Oct. 2, 1964 M/M/vrm. NOR/WW M/ZMA AffO/(WEX win United States Patent 3,303,303 PNEUMATIC SAFETY EDGE FOR PUWER OPERATED DGOR Norman K. Miller, li-llavertown, Pa., assignor to Miller Brothers, Upper Darby, Pin, a partnership Filed Oct. 2, 1964, Ser. No. 401,141 Claims. (Cl. 20061.43)

The present invention relates to a safety edge of a power operated door and is concerned primarily with the elimination of electric contacts within the edge itself.

As the name implies a power operated door is ordinarily moved by an electric motor. It has long been recognized as desirable that the motor be de-energized when the door encounters some object or person in its movement. Thus, the doors have been provided with safety edges. In the past these edges have included electric contacts which when brought .into engagement by the door striking an object disables the motor.

In many places where power doors are installed the liability of an explosion is a serious factor. A good example would be in a factory which produces explosives. In such locations the possibility of the electric contacts in the safety edge creating a spark which would ignite an explosion is a serious danger.

In accordance with the present invention the electric motor which powers the door is located in a safety zone removed from the explosive hazard. Included in the circuit of a motor is a pneumatically operated switch with a piece of tubing extending from the switch to the pneumatic system on the door edge.

In the copending application of Norman K. Miller, Serial No. 341,639; filed: January 31, 1964 and entitled Pneumatic Safety Edge for Power Operated Door, there is illustrated and described a sponge rubber construction that is mounted on a door edge and which provides in effect an air chamber the capacity of which is decreased when the edge encounters an object in its path of movement to create an impulse to operate the switch.

The present invention has in view as its foremost objective the provision of a pneumatic safety edge that is highly simplified as compared to the edge of said application.

More in detail, the invention has as an object the provision of a pneumatic s'afety edge of the character indicated which includes a tube of rubber or a comparable flexible material which is enclosed in a foam rubber structure which is substantially coextensive with the door edge on which it is mounted. Such a door edge may be easily and cheaply manufactured.

In some installations, a door edge may be sufficiently wide to accommodate and require more than one of such tubes. Thus, a further object is to provide a pneumatic safety edge of the character indicated which comprises a foam rubber structure enclosing a plurality of flexible tubes which extend lengthwise of the door edge.

When a plurality of tubes is included it is of course, necessary that they be connected. Thus, another object is to provide, in a pneumatic safety edge of the type noted, a manifold which is connected to the tube ends and is in turn connected to the pneumatically operated switch. In cases where two tubes are employed, the manifold may take the form of a simple T.

Various other more detailed objects and advantages of the invention such as arise in connection with carrying out the above noted ideas in a practical embodiment will 3,303,303 Patented Feb. 7, 1967 in part become apparent and in part be hereinafter stated as the description of the invention proceeds.

The invention therefore comprises a pneumatic safety edge for power operated doors which consists essentially of a foam rubber structure in which is encased one or more flexible tubes extending lengthwise of the door edge and a tube connecting the encased tubes to a pneumati cally operated switch.

For a full and more complete understanding of the invention reference may be had to the following description and accompanying drawing, wherein:

FIGURE 1 is a diagrammatic view of a power operating door with the safety edge of this invention applied thereto.

FIGURE 2 is a horizontal section through the safety edge and a portion of the door.

FIGURE 3 is a view taken normal to the showing of FIGURE 2 and is partly in section and partly in elevation and,

FIGURE 4 is a detailed prospective illustrating the tube connection.

Referring now to the drawing and first more particularly to FIGURE 1 the wall of a building, such as an explosives factory, is indicated at 10. Slidedly mounted in the wall 10 is a door 11. The door 11 is moved by a motor represented diagrammatically at 12 in FIGURE 3. A control switch 13 is included in the circuit of the motor 12, and, in the embodiment of the invention illustrated when the switch 13 is closed the motor is disabled.

At this point it might be well to note that the door 11 is shown to be of a sliding type. The invention is equally susceptible of use on a hinged or collapsible door.

Mounted on the free edge of the door 11 is a safety edge which is referred to in its entirety by the reference character S. The safety edge S comprises a base 14 of foam rubber which takes the form of a block of rectangular formation. A second block 15 of foam rubber which may be somewhat less in thickness than the block 14 is spaced therefrom by three separating strips 16, 17, and 18, also of foam rubber. These strips 16, 17, and 18 are spaced apart and provide chambers 19 and 20 which extend lengthwise of the door edge and are substantially coextensive therewith.

Positioned in the chamber 19 is a flexible tube 21 and 'a similar flexible tube 22 is positioned in the tube 29. Tubes 22 and 21 may be of rubber or a comparable material that is air impervious and has the required property of flexibility.

At one end, preferably the bottom, each of the tubes is closed, the closed ends being repersented at 23. A manifold is applied to the other end of the tubes which in this instance is the upper end. This manifold takes the form of a simple T having a cross head 25 and a stem 26. From the stem 26 another tube 27 extends to the pneumatically operated switch 13.

The blocks 14 and 15 and outer strips 16 and 18 are enclosed by an air impervious lining 28 which may be of vinyl or any suitable plastic and the lining 28 is in turn enclosed by a fabric casing 29.

The lining 23 and fabric 29 are continued out at one side to provide an attaching flap 30 that is employed in mounting the edge S on the door 11.

The operation of the above described safety edge is believed to be obvious from the illustration of the drawing and description of the parts given. However, it may be briefly outlined by noting that when the edge S encounters an object in the path of movement of the door 11, one or both of the tubes 21 and 22 will be deformed to decrease their volumetric content. This results in an increase of pressure of air within the tubes which is translated into an impulse which is transmitted through the tube 27 to the switch 13. When the latter is because various modifications of these details may be provided in putting the invention into practice within the purview of the appended claims.

What is claimed is:

1. In combination, a door, an electric motor for operating the door, a pneumatically controlled switch remote from the door and electrically connected to the motor, an elongate foam-rubber structure extending along and projecting from the closing edge of the door, said structure having a longitudinally extending internal chamber substantially coextensive therewith, a first tube of air-impervious flexible material having one end closed and disposed longitudinally within said chamber substantially coextensive therewith, said tube being configured for snug conforming engagement in said chamber and held by the walls thereof against displacement in said chamber while being deformable under pressure deforming said structure, a second tube of air-impervious material connected in fluid communication between the other end of said first tube and said switch to transmit a fluid-pressure impulse therebetween and operate said switch.

2. The combination according to claim 1, said struc ture having a second internal chamber extending longitudinally of and spaced from said first-mentioned chamber, an internal foam-rubber Wall separating said first and second chambers, a third tube of air-impervious flexible'material having one end closed and disposed longitudinally within said second chamber substantially coextensive therewith, said third tube being configured for snug conforming engagement in said second chamber and held by the walls thereof against displacement in said second chamber while being deformable under pressure deforming said structure, and a manifold interconnected in fluid communication between the other ends of said first and third tubes and said second tube.

3. In a pneumatic safety edge for power operated door that is actuated by a motor having a pneumatically controlled switch, a base of foam rubber, a block of foam rubber spaced from said base, a plurality of separating strips between said base and block and spaced apart to provide chambers extending lengthwise of the edge of said door, a flexible tube snugly received in each of said chambers, said tubes each engaging the Walls of the respective chamber to resist displacement therein while being deformable under pressure deforming said chambers, a manifold connecting said tubes at one end and a tube operatively connecting said manifold to said switch.

4. The safety edge of claim 3 together with a waterproof casing enclosing said base, block, separating strips, and tubes and presenting a flap that is adapted to mount said safety edge on said door.

5. The safety edge of claim 3 together with a plastic lining encasing said base, block, and outer separating strips, and a fabric casing about said lining, said lining and encasing provide a flap that is adapted to mount the safety edge on a door.

References Cited by the Examiner UNITED STATES PATENTS 1,975,828 10/1934 Conklin 200-86 2,561,663 7/1951 Keckley 200-86 2,783,325 2/1957 Luckey ZOO-86 2,843,690 7/1958 Miller ZOO-61.43 3,133,167 7/1964 Miller 20061.43

BERNARD A. GILHEANY, Primary Examiner. J. BAKER, Assistant Examiner. 

1. IN COMBINATION, A DOOR, AN ELECTRIC MOTOR FOR OPERATING THE DOOR, A PNEUMATICALLY CONTROLLED SWITCH REMOTE FROM THE DOOR AND ELECTRICALLY CONNECTED TO THE MOTOR, AN ELONGATE FOAM-RUBBER STRUCTURE EXTENDING ALONG AND PROJECTING FROM THE CLOSING EDGE OF THE DOOR, SAID STRUCTURE HAVING A LONGITUDINALLY EXTENDING INTERNAL CHAMBER SUBSTANTIALLY COEXTENSIVE THEREWITH, A FIRST TUBE OF AIR-IMPERVIOUS FLEXIBLE MATERIAL HAVING ONE END CLOSED AND DISPOSED LONGITUDINALLY WITHIN SAID CHAMBER SUBSTANTIALLY COEXTENSIVE THEREWITH, SAID TUBE BEING CONFIGURED FOR SNUG CONFORMING ENGAGEMENT IN SAID CHAMBER AND HELD BY THE WALLS THEREOF AGAINST DISPLACEMENT IN SAID CHAMBER WHILE BEING DEFORMABLE UNDER PRESSURE DEFORMING SAID STRUCTURE, A SECOND TUBE OF AIR-IMPERVIOUS MATERIAL CONNECTED IN FLUID COMMUNICATION BETWEEN THE OTHER END OF SAID FIRST TUBE AND SAID SWITCH TO TRANSMIT A FLUID-PRESSURE IMPULSE THEREBETWEEN AND OPERATE SAID SWITCH. 